元阳梯田不同土地利用类型表层土壤的抗冲性

为了研究云南省元阳县梯田核心区土壤的侵蚀特性和保水机制,采用原状土冲刷槽法和实地放水冲刷试验法,结合有林地、灌木林地、荒草地和坡耕地的物理性质等,对元阳梯田核心区上述4种土地利用类型表层土壤抗冲性及其主要影响因素进行研究。结果表明:研究区表层土壤抗冲性由强到弱表现为荒草地>灌木林地>有林地>坡耕地;含沙量随着坡度(15°、30°和45°)和冲刷流量(1.5、2.5和3.0 L/min)的增加而增加,坡耕地具有较弱的抗冲性;土壤中的须根能够增强土壤的抗冲能力,特别是直径<1.0 mm的须根具有较强的固结性;土壤的水稳性团聚体越多土壤的抗冲性也就越好,荒草地和灌木林地表层土壤直径>3 mm的土粒,其结构水稳度为93.33%。

Anti-scourability of surface soil of different land use types in area of Yuanyang terrace

On the basis of undisturbed soil erosion groove method and the field scouring test method with the physical properties of woodland,shrub land,waste grassland and slope farm land,the anti-scourability of surface soil of those four land use types and the main influencing factors were studied in core area of Yuanyang County with the purpose of studying the soil erosion characteristics and the mechanism of water conservation.The results showed that the anti-scourability of surface soil of waste grassland was the best,and then followed by shrub land,forest land and slope farm land.With the increase of slope and the water flow the sediment amount increased as well,slope farm land had weak anti-scourability.The fibrous roots could enhance the soil anti-scourability,especially the roots with diameter less than 1.0 mm had strong consolidation.If there were more water-stable aggregate,the anti-scourability was stronger.If the diameter of soil particle in surface soil of waste grassland and shrub land was larger than 3.0 mm,the water-stable aggregates content was 93.33%.